A FRAME ASSEMBLY FOR A ONE STEP ENTRY FRONT ENGINE PASSENGER BUS

FIELD OF THE INVENTION

The present invention relates to a frame assembly for a low floor bus. More specifically relates to a profile of a frame side member and construction of the frame assembly for a one step entry front engine passenger bus.

BACKGROUND OF THE INVENTION

In the current world, the technology is playing a major role for the success of a vehicle. With the advancement of technology, better ride and more comfort have become the primary requirements of the end customers. In current scenario, semi-low floor front engine passenger buses have more than two stage stepping entry which has a minimum dimension of about 250mm each. It poses difficulty to senior citizens and disabled passengers for stepping in or stepping out of buses, particularly city buses. With this constraint, city buses take more time at bus stops for the ingress and egress of passengers, especially in peak traffic hours. Currently available low floor buses with floor height of about 650 mm and below are with rear engines. These low floor rear engine buses reduce the ingress and egress time, but are substantially higher cost compared to existing front engine buses. The following points can be considered for the advantages of front engine buses over the buses having engine at the rear end.

1. Front engine buses are more fuel efficient compared to rear engine buses.

2. Maintenance cost is high for rear engine buses as compared to front engine buses.

3. Dust-ingress in rear engine compartment is more, thus causing higher maintenance cost.

4. Larger cooling system and larger fan are required for buses with rear engine due to poor air flow from the side of the bus, leading to higher power absorption from the engine, hence the high fuel consumption.

5. Premature failure of rear engine compared to front engine

6. Detectability of engine malfunction while driving is low on rear engine in comparison to front engine.

7. Rear engine buses have transverse steps in rear saloon area causing additional fatigue to conductor when he moves to collect fare and give tickets. Similarly, old passengers and children also face difficulty in climbing the transverse steps to reach the rear saloon area.

The main concern in case of low floor buses is the space between the axle and the frame which is critical in case of packaging the required suspension systems and for axle clearance. In case of one step entry rear engine passenger buses, the frame for the whole length of the vehicle will not be in a single level. The whole frame is divided into three different portions along its length and joined by puddle welding with the help of plates connecting the two members as shown in the Fig 1. The rear portion will be raised to two step entry floor level from the one step entry floor level in order to accommodate the suspension components along with axle and also the mounting of the engine in rear is at a higher level with enough ground clearance. The front portion also will be raised to two step level for axle clearance but it will have a cut out for entry step and a sunken gangway( floor will be supported by the bottom flange of side member instead of top flange). The middle portion of the frame will be in the height of about 650mm for one step entry passenger buses.

The floor starting just before the rear axle up to the rear end of the bus will be at a two step entry height (about 900mm)when compared with middle portion of the frame which is at one step entry height (about 650mm). Therefore the departure angle as per the legal requirement can be easily met. Further the floor height is non uniform from front to rear of the vehicle.

Frame assembly for the one step entry rear engine passenger bus currently consists of one or more parts of frame side members, cross members and outriggers which are welded together. The entire cross members connecting the frame side members are welded or riveted inline with the outriggers to the frame side member as shown in the Fig 1. Therefore the whole frame structure is comparatively heavier and more costly and time consuming to produce. Hence, there is a need to provide a one step entry front engine passenger bus with seamless frame side member.

OBJECT OF THE INVENTION

In order to solve any one of the above described problems, the present invention provides a one step entry front engine passenger bus with seamless frame side member. The one step entry front engine passenger bus comprising of at least two parallel longitudinal frame side members constructed using three channels with different profiles to achieve the suitable space for the axle clearance and suspension packaging.

Another object of the present invention is to provide the lighter and economical bolted frame for one step entry front engine bus rather than conventional welded or riveted construction.

Yet another object is to provide different positions for doors on the frame assembly for one step entry front engine passenger bus.

Further object is to meet departure angle as per the legal requirements for one step entry front engine passenger bus by tapering the fag end of rear portion of frame side members at a predetermined angle, as the entire floor level from front to rear of the proposed bus is at one step entry level.

SUMMARY OF THE INVENTION

According to one aspect, the present invention, which achieves the objectives, relates to a frame assembly of one step entry front engine passenger bus. The frame assembly of the present invention comprises of at least two parallel multi channel constructed longitudinal frame side members spaced apart from one another, a plurality of transverse cross members connecting the two longitudinal frame side members and a plurality of outriggers which form the extensions of plurality of transverse cross members outside the frame side members. Frame side member is preferably of three channel constructions such as first, second and third channels with different profile shapes to accommodate the suspension systems and the axles with minimal welding or riveting. The cross members are provided for supporting the drive train components like engine, propeller shaft, suspension linkages and for fixing all other related necessary items. Doors at different locations can be positioned by properly choosing the cross members location, without changing the frame structure. The outriggers are bolted together with the frame side member and cross members instead of traditional welding/ riveting process followed for one step entry rear engine passenger bus. This results in weight saving and ease of manufacturing. The outriggers form the base for the floor space incases of one step entry front engine passenger buses.

In one embodiment of the present invention, first channel of frame side member is front positioned and configured to include a bent portion which is bending inwardly in the direction of central line of a frame. The second channel is provided with a curved hump is middle positioned and the third channel is rear poisoned on a frame side member with tapering at fag end to ensure that the predetermined departure angle is achieved to avoid body or frame hitting the ground during bumps and to clear the ramps while climbing and departing the flyovers. The second channel is joined with both the first and third channels to make complete frame side member for a one step entry front engine rear driven passenger bus.

In another preferred embodiment of the present invention, first channel of frame side member is rear positioned and configured to include a bent portion which is bending inwardly in the direction of central line of a frame and also tapered at fag end to ensure that the predetermined departure angle is achieved to avoid body or frame hitting the ground during bumps and to clear the ramps while climbing and departing the flyovers The second channel is provided with a curved hump is middle positioned and the third channel is front positioned on a frame side member. The second channel is joined with both the first and third channels to make complete frame side member for a one step entry front engine front driven passenger bus.

Various objects and advantages of this invention will become apparent to those skilled in the art from the following description, when read in light of accompanying drawings.

BRIEF DISCRIPTION OF THE ACCOMPANYING DRAWINGS

The advantages and features of the invention will become more clearly apparent from the following description which refers to the accompanying drawings given as non- restrictive examples only and in which:

Figure 1 shows a frame assembly for one step entry rear engine passenger bus in accordance with the prior art.

Figure 2 shows a frame assembly for one step entry front engine rear driven passenger bus in accordance with the present invention.

Figure 3 shows frame side members of the frame assembly of a Figure 2. Figure 4 shows an outriggers assembly on the frame side members of Figure 2. Figure 5 shows an exploded view of a first channel of frame side members of a Figure 3. Figure 6 shows an exploded view of a second channel of frame side members of a Figure 3.

Figure 7 shows an exploded view of a third channel of frame side members of a Figure 3.

Figure 8 shows the arrangement of first, second and third channels on the frame side member for the one step entry front engine rear driven passenger bus

Figure 9 shows the arrangement of first, second and third channels on the frame side member for the one step entry front engine front driven passenger bus

Figure 10 shows the indications of different door positions on the frame assembly for the one step entry front engine passenger bus.

DETAILED DESCRIPTION OF THE INVENTION

The frame assembly for a one step entry front engine passenger bus is described in the following description. Expressions used in this description such as front, middle and rear are with respect to the forward direction of the bus.

Fig .2 shows the frame assembly for the one step entry front engine passenger bus. The frame assembly comprises of at least two parallel multi channel constructed longitudinal frame side members (1) spaced apart from one another and a plurality of cross members (2) connecting the frame side members (1) and plurality of outriggers (3). Every cross member has extensions outside the frame side members (1) called outriggers (3).

Frame side members (1) are constructed of sheet metal and bent into channel shapes, preferably of three channel construction such as first (4), second (5) and third channels (6) as shown in Fig 3. Three channels are constructed with different profile shapes to achieve the suitable space for the axle clearance and suspension components packaging. The suspension components comprising of pedestal, spring, and shock absorber, anti roll bar, radius rods, V rods and bellow bracket. The channels are formed and rolled separately and then puddle welded together to form the longitudinal frame side member (1) for the one step entry front engine passenger bus. The cross members (2) are of different type each having different purpose like supporting the drive train components comprises of engine, propeller shaft and for fixing all other related necessary item.

Furthermore, an arrangement of outriggers (3) on the frame side member (1) for a one step entry front engine passenger bus is shown in Fig. 4. The outriggers (3) are the extensions of the cross members (2) outside the frame side member (1) which form the supports for the seat mounting members and the floor. The outriggers (3) forms the bases for the floor space incase of one step entry front engine passenger bus. Outriggers (3) are bolted (7) together on to the frame side members (1) and the cross members (2) instead of traditional welding to reduce the weight and ease of manufacturing They are tapered C channels (8) with stiffeners (9) and end gussets (10) for mounting it. All the outriggers ends are provided with plates or connector plates (11) which directly get welded on to the pillars of the bus body structure.

This design eliminates the use of sole bars as in conventional design required for integration of the frame with the body structure. Sole bars are the channel shaped members running longitudinally at the end of the outriggers.

This result in considerable weight reduction, less frame assembly time and hence high manufacturability.
The top surfaces of the outriggers are placed in line with the frame side member top flange (12). This creates a flat platform for the integration of the floor structure with the frame, thus avoiding additional support beams for floor which helps in achieving the required floor height.

In one of the embodiment of present invention as shown in the Fig 2, the frame assembly for one step entry front engine rear driven passenger bus is presented. The frame assembly comprises of two parallel multi channel constructed longitudinal frame side members (1), plurality of cross members (2) and plurality of outriggers (3). Frame side members (1) are of three channel construction namely first (4), second (5) and third channels (6) as shown in Fig 3.

Referring to Fig. 5, the first channel (4) of the frame side member of Fig 3 is shown. The first channel (4) is configured to include a bent portion (13) which is bending inwardly in the direction of central line of the frame. The bent portion is obtained by providing multiple bends (14), preferably four bends so that the actual frame width (Wl) decreased gradually to a point (W2) and then it is maintained for some distance and then again it gradually increased to the original width (Wl). This profile is made to fix the suspension components in order that none of the suspension components projected above the frame top flange to have the flat saloon space.

The second channel (5) is a highly curved hump (15) which is a formed component of steel as shown in Fig 6. The depth of the curve (15) depends on the axle profile and travel dimension. The third channel (6) of the frame side member (1) is also a channel member rolled from sheet metal. The fag end of the third channel (6) is tapered (16) at an angle to ensure that the predetermined departure angle is achieved, to avoid body or frame hitting the ground during bumps and to clear the rams while climbing and departing the flyovers as shown in the Fig 7. The departure angle corresponds to the distance along the longitudinal axis to the least favorably placed point in the rear of the rearmost axle from the center line of the rearmost axle and its height from the ground shall be established to the nearest millimeter.

The first channel (4) with bends is front positioned (17), second channel is middle positioned (18) and the tapered third channel is rear positioned (19) on a frame side member (1). The second channel (5) is welded or riveted with first and third channels to make elongated longitudinal frame side member of a frame assembly for one step entry front engine rear driven passenger bus as shown in Fig 8.

In another embodiment of the present invention, frame side assembly for one step entry front engine front driven passenger bus is presented. The frame assembly comprises of two parallel multi channel constructed longitudinal frame side members (1), plurality of cross members (2) and plurality of outriggers (3) .Frame side members (1) are of three channel construction namely first channel (4), second channel (5) and third channel (6).

The first channel is configured to include a bent portion (24) which is bending inwardly in the direction of central line of the frame. The bent portion (24) is obtained by providing multiple bends, preferably four bends so that the actual frame width (Wl) decreased gradually to a point (W2) and then it is maintained for some distance and then again it gradually increased to the original width (Wl). This profile is made to fix the suspension components in order that none of the suspension components projected above the frame top flange to have the flat saloon space. Further, the fag end of the first channel is tapered (23) at an angle to ensure that the predetermined departure angle is achieved. The second channel (5) is a highly curved hump (15) which is a formed component of steel. The depth of the curve (15) depends on the axle profile and travel dimension.

The first channel with bends and tapering is rear positioned (20), second channel is middle positioned (21) and the third channel is front positioned (22) on a frame side member. The second channel is welded or riveted with first and third channels to make elongated longitudinal frame side member of a frame assembly for one step entry front engine front driven passenger bus as shown in Fig 9.

The cross members (2) and the outriggers (3) are arranged on frame side members (1) of one step entry front engine passenger bus in such a way that the doors (D) can be provided at any of the positions on the driver side (right hand side) and the co driver side (left hand side), by using the same base frame assembly as shown in the Fig 10.

Different door combinations on driver side (right hand side) with door aperture of about 1350mm are positioned at three locations; first door opening is immediately after front axle, second is immediately ahead of rear axle and third is immediately after the rear axle. The door combinations on co- driver side (left hand side) with door aperture of about 1350mm are positioned at three different locations; first is immediately after the front axle, second is immediately ahead of rear axle and third is immediately after the rear axle. Further, another door opening on co driver side (left hand side) with door aperture of about 850mm is positioned immediately ahead of front axle as shown in Fig. 10. The location of outriggers plays a major role in propeller shaft layout as all the centre bearing of the individual propeller shafts has to be supported by the cross member and outrigger assembly.

WE CLAIM:

1. A frame assembly for a one step entry front engine rear driven passenger bus , the frame assembly comprising:

at least two parallel multi channel constructed longitudinal frame side members (1) comprising of a first channel (4) ,a second channel (5) and a third channel (6), wherein said second channel (5) connects the first channel (4)and said third channel (6);

the first channel (4) is front positioned (17) and configured to include a bent portion (13) which is bend inwardly in the direction of central line of a frame, the second channel (5) having a curved hump (15) is middle positioned (18) and the third channel (6) is rear positioned (19) on said frame side members (i);

a plurality of transverse cross members (2) connecting the frame side members (1); and

a plurality of outriggers (3), which forms the extensions of both the ends of the plurality of transverse cross members (2) outside the frame side members (1) and joined together with the multi channel constructed longitudinal frame side members (1) and said plurality of transverse cross members (2).

2. The frame assembly as claimed in claims '1', wherein the profile of said third channel (6) of said multi channel constructed longitudinal frame side member (1) is preferably tapered (16) at fag end at an angle to avoid hitting the frame to the ground during bumps and to clear ramps.

3. A frame assembly for a one step entry front engine front driven passenger bus, the frame assembly comprising:

at least two parallel multi channel constructed longitudinal frame side members (1) comprising of a first channel, a second channel and a third

channel (6), wherein said second channel connects the first channel and said third channel;

the first channel (4) is rear positioned (20) and configured to include a bent portion (24) which is bend inwardly in the direction of central line of a frame, the second channel (5) having a curved hump is middle positioned (21) and the third channel (6) is front positioned (22) on said frame side members;

a plurality of transverse cross members (2) connecting the frame side members (1); and

a plurality of outriggers (3), which forms the extensions of both the ends of the plurality of transverse cross members (2) outside the frame side members(l) and joined together with the multi channel constructed longitudinal frame side members (1) and said plurality of transverse cross members (2).

4. The frame assembly as claimed in claims '3', wherein the profile of said first channel (4) of said multi channel constructed longitudinal frame side member (1) is preferably tapered (23) at fag end at an angle to avoid hitting the frame to the ground during bumps and to clear ramps.

5. The frame assembly as claimed in claims '1' and '3', wherein said second channel (5) connects the first channel (4) and the third channel (6) by means of welding or riveting.

6. The frame assembly as claimed in claims '1' and '3', wherein said bent portion (13,24) of first channel (4) is obtained by providing multiple bends (14) in such a way that the width of said base frame assembly is gradually decreased to a point and then it is maintained for some distance and then again it gradually increased to a original value.

7. The frame assembly as claimed in claims '1' and '3', wherein said bent portion (13,24) of said first channel (4) and curved hump (15) of said second channel (5) are provided to accommodate the suspension components , the front and rear axels and the frame or axle displacement during bumps and normal travel.

8. The frame assembly as claimed in claims '7', wherein said suspension components comprising of air spring pedestal, air spring, shock absorber, anti roll bar, radius rods, V rods and bellow bracket.

9. The frame assembly as claimed in claims '1' and '3', wherein said outriggers (3) are joined with the frame side member (1) and the plurality of transverse cross members (2) using bolted nuts.

10. The frame assembly as claimed in claims '1' and '3', wherein said outriggers (3) are provided with connector plates (13) without sole bar for integration of said frame assembly to a bus body.

11. The frame assembly as claimed in claims '1' and '3', wherein said plurality of transverse cross members (2) and said plurality of outriggers (3) are arranged in one or more locations on the frame side member (1) to provide one or more door openings without changing the frame assembly.

12. The frame assembly as claimed in claims '11', wherein at least three door openings are provided on a driver side/right hand side and at least four door openings on a co driver side /left hand side.

13. The frame assembly as claimed in claims '1' and '3', wherein said multi channel constructed longitudinal frame side member (1) is formed of a metal sheet.

14. The frame assembly as claimed in claims '1' and '3'; wherein said plurality of outriggers (3) forms the support for seat mounting members and a floor.

15. The frame assembly as claimed in claims '1' and '3',wherein said plurality of outriggers (3) provides flat platform for the integration of floor structure with the frame assembly by placing the top surface of said outriggers in line with the frame side member top flange.

16. The frame assembly as claimed in claims '1' and '3',wherein depth of curved hump (15) of said second channel (5) depends on said axle profile and travel dimension and said multiple bends in the bent portion (13,24) of the first channel (4) depends on said suspension components packaging.